POWER DRIVEN VENTING OF A VEHICLE

Abstract: An obstruction detection apparatus (44) is provided for use in closing a power driven vent, such as a window, that is located in an opening. The vent includes a first closing edge that moves as the vent is closed and the opening includes a second closing edge that is contacted by the first closing edge when the vent is in a fully closed position. The apparatus includes a detector (52) configured to detect an obstruction at points all along the second closing edge without requiring contact between the obstruction and the vent and to deliver a detection signal when an obstruction is detected. A controller (46) is connected to the detector for receiving the detection signal and delivering a corresponding alarm signal (48).

Description: POWER DRIVEN VENTING OF A VEHICLE Background of the Invention The invention relates to power driven venting of a vehicle. Early automobiles for example, included stationary windows that allowed an occupant of the automobile to view regions outside of the automobile. Over time, these stationary windows evolved into adjustable windows that could be opened to provide ventilation to the interior of the automobile. The adjustable windows, which were initially hand lifted, were followed first by manually cranked windows, and then by the power operated windows commonly found in automobiles today. Eventually, it was discovered that the power operated windows could be automatically opened to provide ventilation when the interior of the automobile became too hot and automatically closed when rain was detected. This automatic venting system, which is described in United States Patent No. 4,852,469 and incorporated by reference, then evolved into the automobile environment management system described in United States Patent No. 5,054,686 and also incorporated by reference. Summary of the Invention In general, in one aspect, the invention features an obstruction detection technique for use in closing a power driven vent, such as a window, that is located in an opening. The vent includes a first closing edge that moves as the vent is closed and the opening includes a second closing edge that is contacted by the first closing edge when the vent is in a fully closed position. A detector is configured to detect an obstruction at points all along the second closing edge without requiring contact between the obstruction and the vent. When the detector detects such an obstruction, the detector delivers a detection signal to a controller. The controller receives the detection signal and delivers a corresponding alarm signal that is used, for example, to open the window. The technique ensures that powered vents such as windows or sunroofs can be automatically closed without risk of injury to children, pets, or other occupants of a vehicle in which the vents are installed. Embodiments of the invention may include the following features. The detector may include an optical detector, an infrared detector, ar. ultrasound detector, or similar devices. The detector may deliver the detection signal in response to an increase in energy received at the detector, and there may also be an emitter that emits energy so that the detector delivers the detection signal in response to an increase or a decrease in a reflected portion of the energy produced by the emitter and received by the detector. The detection signal may have a characteristic which represents the intensity of the energy received. For example, the detector may produce pulses having durations related to the intensity of the energy received by the detector and deliver the detection signal when the duration of one pulse exceeds a predetermined value, or when the durations of a predetermined number of consecutive pulses exceed the predetermined value. The predetermined value may be related to the duration of a pulse when no obstruction is present or the average duration of pulses produced when no obstruction is present and the vent moves between an opened position and a closed position. The predetermined value may include a correction factor that accounts for variations in the duration of pulses produced when no obstruction is present, and may vary based on the position of the vent. The predetermined value, or some other value indicative of an obstruction free opening, may be stored during an initialization procedure. The detector and emitter may be included in an integral unit, which may be a compact unit in which the detector and the emitter share a common lens. The emitter may include a light emitting diode or a laser device. The emitter may also includes a lens that emits a fan shaped energy curtain. There may also be a second detector configured to detect an obstruction at any point along the second closing edge without requiring contact between the obstruction and the vent and to deliver a second detection signal when an obstruction is detected. The first and second detectors may be arranged so that they are not caused to deliver the first and second detection signals as a result of energy received at the same time. There may also be a first emitter positioned to emit a first energy signal toward the first detector, and a second emitter positioned to emit a second energy signal toward the second detector, with the first and second emitters producing the first and second energy signals in an alternating manner, and the controller being connected to the second detector and to deliver the alarm signal in response to the first or second detection signals. The detectors may be configured so that, when the first emitter is emitting the first energy signal, the first detector delivers the first detection signal in response to a decrease in energy received at the first detector, and the second detector delivers the second detection signal in response to a decrease in energy received at the second detector, and when the second emitter is emitting the second energy signal, the first detector delivers the first detection signal in response to an increase in energy received at the first detector, and the second detector delivers the second detection signal in response to an increase in energy received at the second detector. The first detector may be screened from the second emitter and the second detector may be screened from the first emitter. Automatic closing or opening of the vent may be initiated by a rain sensor, a temperature sensor, a motion sensor, or a light sensor. Closing of the vent may also be initiated by a manual switch. In another aspect, generally, the invention features a technique for controlling power driven windows of an automobile. There are driver control switches accessible at the driver's position, separate passenger control switches accessible at a passenger position, and microprocessor control circuitry for responding to switching of the driver and passenger control switches for controlling the power driven windows. The microprocessor control circuitry is programmable in response to the driver control switches and separately programmable in response to the passenger control switches. Embodiments of the invention may include one or more of the following features. The microprocessor control circuitry may respond to switching of the driver control switches when a conflict arises between the driver control switches and the passenger control switches. There may be passenger control switches located at two additional passenger positions and a lockout switch at the driver's position that, when active, causes the microprocessor control circuitry to ignore switching of the additional passenger control switches in response to the lockout switch. This feature could be used, for example, to disable window controls for the rear window of an automobile when children are present in the back seat. The driver control switches need not be directly connected to the vent driving circuits, and the microprocessor controller may be located remotely from the driver control switches. The driver control switches may be connected to the microprocessor controller by 20 gauge or finer wire. The technique provides failsafe operation in that it is designed so that a failure in the obstruction detection apparatus will prevent automatic vent closure. This ensures that a system failure will not result in injury. However, the apparatus also includes a manual switch that can override the obstruction detection features. Thus, in the event of a failure of the obstruction detection system, the vents can still be closed through the manual override. In another aspect, generally, the invention features automatically opening a power driven vent in response to the opening of the door to reduce air pressure build up when closing a door of the vehicle. This substantially reduces the force necessary to close the door. This feature may also include automatically closing the vent after the doors are closed, and may further include detecting obstructions while automatically closing the vent without requiring contact between the obstruction and the vent. In another aspect, generally, the invention features monitoring the position of a power driven vent by a generating a count of current ripples in a circuit that moves the vent. This count can then be compared against a measure of the number of current ripples generated as the vent moves from a first known position to a second known position (e.g., from fully closed to fully open) . The count of current ripples can be incremented as the vent is, for example, opening, and decremented as the vent is, for example, closing. Other advantages and features will become apparent from the following description and from the claims. Brief Description of the Drawings Fig. 1 is a side view of an automobile with closed doors. Fig. 2 is a top view of the automobile of Fig. 1 with open doors. Fig. 3 is a block diagram of an automatic window system. Fig. 4 is a side view of energy curtains produced by an obstruction detection system of the automatic window system of Fig. 3. Fig. 5 is a top view of the energy curtains of Fig. 4. Fig. 6 is a schematic of a front emitter/receiver unit of the system of Fig. 3. Fig. 7 is a block diagram of a photo IC of a receiver of the emitter/receiver unit of Fig. 6. Fig. 8 is a schematic of a rear emitter/receiver unit of the system of Fig. 3. Figs. 9A-9C are schematic views of a compact emitter/receiver unit for use in the system of Fig. 3. Fig. 10 is a flow chart of an obstruction detection procedure of the system of Fig. 3. Figs. 11A-11C are timing diagrams of signals related to the obstruction detection system of Fig. 3. Fig. 12 is a block diagram of a controller of the system of Fig. 3. Figs. 13-15 are flow charts of procedures implemented by the controller of Fig. 12. Figs. 16A-16B are flow charts of a parking mode procedure implemented by the controller of Fig. 12. Fig. 17 is a top view of emitter/receiver placement for an obstruction detection system of the automatic window system of Fig. 3. Fig. 18 is a schematic of a sunroof emitter/receiver unit of the system of Fig. 3. Fig. 19 is a block diagram of a sunroof control system. Figs. 20-29 are flow charts of procedures implemented by a control unit of the sunroof control system of Fig. 19. Fig. 30 shows a block diagram of an obstruction detection system. Fig. 31 shows an obstruction detection system for a window associated with a vehicle door. Fig. 32 shows obstruction detection system for a sun roof associated with a vehicle. Fig. 33 shows the path of an energy signal produced by an obstruction detection system. Fig. 34 shows an obstruction detection system in an environment that includes an ambient light source. Fig. 35 shows a lens and filter system. Fig. 36 shows a shade and filter system. Fig. 37 shows a high frequency pulse modulated signal. Fig. 38 shows a high frequency pulse / low frequency amplitude modulated signal. Fig. 39 shows a pulse synchronization timing diagram. Fig. 40 shows an obstruction detection system including an ambient energy signal receiver. Fig. 41 shows a diverging unit. Fig. 42 shows a partial view of an obstruction detection system including the diverging unit shown in Fig. 41 together with several receiver units. Fig. 43 shows an isometric view of the transmitter/receiver unit shown in Fig. 42. Fig. 44 shows an obstruction detection system including the transmitter/receiver unit shown in Fig. 43. Fig. 45 shows an obstruction detection system including several transmitter/receiver units. Fig. 46 shows an obstruction detection system including a fiber optic waveguide having several notches. Fig. 47 shows a block diagram of an obstruction detection system including a bi-directional transmitter/receiver unit. Fig. 48 shows an obstruction detection system in an environment that includes ambient reflection. Fig. 49 is a schematic block diagram of a circuit which generates and senses a beam that monitors and controls the window. Fig. 50 is a schematic of a vehicle door showing a partially closed window and an arrangement of transmitting and receiving transducers that establish a monitoring beam for a nonlinear, rectilinear window edge. Fig. 51 is a schematic of a vehicle sun roof partially closed showing the arrangement of transducers relative to a nonlinear, curvilinear edge. Fig. 52 is a schematic three-dimensional view of a single sensor corner receiver. Fig. 53 is a schematic three-dimensional view of a dual sensor corner receiver. Fig. 54 is a schematic top plan view of a transducer using a spring-biased interrupter. Fig. 55 is a side elevational view of a transducer accompanied by a camming surface for guiding obstructions into the beam. Fig. 56 is a schematic view showing ambient light from the sun interfering with reception at the receiver. Fig. 57 is a view similar to Fig. 56 wherein the reflected radiation from the transmitter is interfering with the operation of the receiver. Fig. 58 is a schematic view of a transmitter and receiver employing shades according to this invention. Fig. 59 is a view similar to Fig. 58 in which the transmitter and receiver are using both shades and filters. Fig. 60 is a schematic of a dual channel obstruction detection system for a vehicle window according to this invention using different frequencies for each channel. Fig. 61 is a view similar to Fig. 60 wherein the channels may use the same frequency but are operated one at a time. Fig. 62 shows the transmitter and receiver waveforms for each of the channels in Fig. 61. Fig. 63 is a schematic block diagram of a control circuit for operating the dual channel system of Fig. 61. Description of the Preferred Embodiments Referring to Figs. 1 and 2, an automobile 10 often includes a front door 12 and a rear door 14 on each side, with front door 12 having a power operated front window 16, and rear door 14 having a power operated rear window 18. Automobile 10 can also include a power operated sunroof 20. Power operated windows 16, 18 are moved between closed and fully opened positions by electric motors 22 (see Fig. 3) positioned within doors 12, 14, and are operated by window switches 24 positioned on doors 12, 14. Typically, windows 16, 18 are each operated by two motors 22 — one for up and one for down, sunroof is operated by a single meter 27. Typically, the driver's side front door 12 includes a control panel 26 that includes four window switches 24 and allows the driver of automobile 10 to operate all windows 16, 18. Similarly, sunroof 20 is opened and closed by a motor 22 and operated by a sunroof switch 28 that is typically positioned near sunroof 20. Sensors 30 (Fig. 2) indicate whether doors 12, 14 are closed (Fig. 1) or open (Fig. 2) . Similarly, the position of an ignition switch 32 provides a general indication as to whether automobile 10 is occupied (i.e., when ignition switch 32 is on, automobile 10 is probably occupied, and when ignition switch 32 is off, automobile 10 is probably unoccupied) and specifically whether a key has been inserted and which rotary position it is in. Referring also to Fig. 3, a rain sensor 34 positioned on the exterior of automobile 10 detects the presence of rain, and a temperature sensor 36 positioned within automobile 10 monitors the interior temperature of automobile 10. As discussed below, a light sensor 38, a motion detector 40, and a dangerous gas detector 42 can also be installed in automobile 10. Automatic window system 44 includes a controller 46 that uses the signals from the sensors described above to control motors 22. For example, controller 46 responds to an indication from rain sensor 34 that rain is beginning to fall by automatically controlling motors 22 to close windows 16, 18 and sunroof 20. Controller 46 responds to temperature sensor 36 by causing motors 22 to open or close windows 16, 18 and/or sunroof 20. In response to an indication from temperature sensor 36 that the temperature within automobile 10 has exceeded a first threshold value (typically 95° F.), and absent an indication of rain from rain sensor 34, controller 46 causes motors 22 to open windows 16, 18 and/or sunroof 20. Similarly, in response to an indication from temperature sensor 36 that the temperature within automobile 10 has fallen below a second threshold value (typically 55° F.), controller 46 causes motors 22 to close windows 16, 18 and sunroof 20. Temperature sensor 36 can be implemented using a single sensor that measures the temperature and compares it to - li ¬ the two threshold values, or using two sensors, each of which compares the temperature against one of the threshold values. In addition to controlling the environment within automobile 10, system 44 can be configured to provide features such as night closure, intruder detection, and gas detection. When system 44 includes a light sensor 38, windows 16, 18 are automatically closed at night to prevent insects and other nocturnal pests from entering automobile 10. A motion detector 40 can provide intruder detection by, when automobile 10 is unoccupied (as indicated by the position of ignition switch 32) , causing system 44 to automatically close windows 16, 18 and sunroof 20 upon detection of movement. Similarly, a dangerous gas detector 42 can cause system 44 to automatically open windows 16, 18 and/or sunroof 20 upon detection of unacceptable levels of noxious gases such as carbon monoxide. System 44 also provides convenience features such as express open and express close, which allow occupants of automobile 10 to fully open or close windows 16, 18 with a single touch of a window switch 24. In addition, system 44 allows the driver to express open or express close any or all of windows 16, 18 with a single touch at control panel 26. Child guard features that allow the driver to disable the switches 24 positioned on rear doors 14 are also provided. Other features of system 44 provide both security and convenience. For example, system 44 can be configured to automatically close windows 16, 18 and sunroof 20 when ignition switch 32 is turned to the off position, which indicates that the driver and other occupants are exiting automobile 10. This feature, which eliminates any inconvenience associated with closing windows 16, 18 and sunroof 20, is known as security close because it ensures that automobile 10 will not be mistakenly left unattended with the windows open. Another feature, referred to as anti air bind, eases closing of doors 12, 14, and thereby reduces the chance that a door will be mistakenly left ajar. As automobiles have become increasingly air tight, it has been discovered that a significant amount of air pressure is produced by air that is within an automobile while a door is closing. This pressure, referred to as air bind, requires that considerable force be applied to the door to ensure proper closure. System 44 eliminates air bind by partially opening rear windows 18 upon receiving a signal from a sensor 30 that a door 12, 14 is open. The open rear windows 18 drastically reduce the pressure built up within automobile 10 and thereby eliminate the air bind problem. Once system 44 determines, through sensors 30, that all doors 12, 14 are closed, system 44 automatically closes windows 18. System 44 can also be configured to interact with an alarm system 48 or an air conditioning system 50. When system 44 interacts with air conditioning system 50, controller 46 opens windows 16, 18 to allow particularly hot air to be vented from automobile 10. Once controller 46 determines that the temperature within automobile 10 has fallen below a specified value, controller 46 closes windows 16, 18. Because system 44 automatically opens and closes windows 16, 18 and sunroof 20, and often does so without human interaction, system 44 must account for a risk that a window 16, 18 or sunroof 20 will be accidentally closed in a way that pinches or otherwise injures a child, pet, or other occupant of automobile 10. To eliminate this risk, system 44 includes an obstruction detection system 52 that prevents system 44 from accidentally closing a window 16, 18 or sunroof 20 when an obstruction such as a child's arm is present within the path travelled by the window 16, 18 or sunroof 20, and does so without requiring the obstruction to contact the moving window 16, 18 or sunroof 20. Typically, obstruction detection system 52 produces an energy curtain in the region traversed by a closing window 16, 18 or sunroof 20, and detects interference with the energy curtain. As shown in Fig. 3, controller 46 receives control signals from occupants of automobile 10, and particularly from the driver, through signals received from ignition switch 32, window switches 24, sunroof switch 28, and door sensors 30. Controller 46 also responds to signals from rain sensor 34, temperature sensor 36, light sensor 38, motion sensor 40, and dangerous gas detector 42. In addition, controller 46 interacts with obstruction detection system 52 by sending driving signals 54 to system 52 and responding to detection signals 56 produced by system 52. Driving signals 54 cause system 52 to produce energy curtains in windows 16, 18 or sunroof 20, and are typically only produced when controller 46 is preparing to close, or closing, a window 16, 18 or sunroof 20. Controller 46 configures driving signals 54 to only produce an energy curtain in a particular window 16, 18 that is being closed. Controller 46 also monitors electrical characteristics of motors 22 and uses information about the electrical characteristics in controlling motors 22. Window switches 24 and sunroof switch 28, in addition to signalling that windows 16, 18 and sunroof 20 should be opened or closed, provide configuration signals to controller 46. By pressing a window switch 24 immediately after turning off ignition switch 32, the driver can disable security closing, and by pressing the window switch 24 more than once, the driver can configure the extent to which windows 16, 18 are opened upon detection of a signal from temperature sensor 36, with, for example, one additional press corresponding to slightly open and five additional presses corresponding to fully open. Rather than separately configuring each window, the driver can simultaneously configure all windows by pressing the switch 24 corresponding to the left rear window. To enable/disable the anti air bind system, the driver simultaneously presses the switches 24 corresponding to the right and left rear windows. When switches 24, 28 are used for system configuration, controller 46 provides feedback to the driver through a feedback unit 58. Feedback may be provided through audible tones that reflect the number of times that the driver has pressed switches 24, 28. Feedback could also be provided through an LED or LCD display, or through other means. Though use of switches 24, 28 for configuration reduces the number of switches required and eases installation, a separate set of configuration controls could also be used. Because system 44 relies on many preexisting sensors and controls, system 44 can be easily installed in an existing automobile 10. For example, in many systems, controller 46, obstruction detection system 52, feedback unit 58 (which is typically a buzzer) , rain sensor 34, and temperature sensor 36 are the only new components. Moreover, because many functions of controller 46 are implemented in software, controller 46 can be easily customized or upgraded as new features become available. Referring to Fig. 4, obstruction detection system 52 includes front emitter/receiver units 60 positioned to produce energy curtains 62 in regions traversed by front windows 16, and rear emitter/receiver units 64 positioned to produce energy curtains 66 in regions traversed by rear windows 18. Emitter/receiver units 60, 64 include emitters 68 (see Fig. 6) that produce energy curtains 62, 66 and receivers 70 (see Fig. 6) that detect any portion of energy curtains 62, 66 that is reflected back to emitter/receiver units 60, 64. When obstructions are placed within energy curtains 62, 64, the reflected portions of energy curtains 62, 74 increase. Thus, receivers 70 detect obstructions by detecting increases in the reflected portions of energy curtains 62, 66. Front emitter/receiver unit 60 is vertically positioned at the lower front corner of window 16. This positioning ensures that energy curtain 62 covers the region ABCD in which an obstruction could be caught between window 16 and a window frame portion 72 of door 12 as window 16 closes. This positioning also minimizes the vertical angle a-^ of energy curtain 62 needed to cover region ABCD, which, could be, for example, about 38°. Because the area covered by energy curtain 62 is directly related to the vertical angle ct 1 , and the intensity of energy curtain 62 is inversely related to the area covered by energy curtain 62, minimizing the vertical angle λ maximizes the intensity of the energy curtain 62 that can be produced by a particular emitter 68. Because the sensitivity of front emitter/receiver unit 60 is directly related to the intensity of energy curtain 62, the positioning of front emitter/receiver unit 60 maximizes the ability of front emitter/receiver unit 60 to detect obstructions. The position of front emitter/receiver unit 60 is also aesthetically pleasing and allows for efficient installation. Rear emitter/receiver unit 64 is horizontally positioned at the lower front corner of window 18. This positioning ensures that energy curtain 66 covers the region EFGHI in which an obstruction could be caught between window 18 and a window frame portion 74 of door 14 as window 18 closes. As with front emitter/receiver unit 60, the positioning of rear emitter/receiver unit 64 minimizes the vertical angle α 2 of energy curtain 66, which may vary from about 50° to 60° depending on the configuration of a particular window 18. This positioning maximizes the intensity of energy curtain 66 and thereby maximizes the ability of rear emitter/receiver unit 64 to detect obstructions. Referring to Fig. 5, emitter/receiver units 60, 64 are positioned so that horizontal angles B λ and B 2 of energy curtains 62, 66 are roughly centered, respectively, in window frame portion 72 of door 12 and window frame portion 74 of door 14. This positioning ensures that, even if an emitter/receiver unit 60, 64 is misaligned due to vibrations or other adverse operating conditions present in automobile 10, energy curtains 62, 66 will detect obstructions in the planes defined by windows 16, 18. These same alignment concerns are addressed by combining emitters 68 and receivers 70 in emitter/receiver units 60, 64 to eliminate any installation difficulties that would be associated with aligning separately packaged emitters 68 and receivers 70, and to eliminate maintenance and operational difficulties that could result from to misalignment stemming from vibrations or other adverse operating conditions. Referring to Fig. 6, front emitter/receiver unit 60 includes an emitter 68 and two receivers 70. Emitter 68 includes four infrared light emitting diodes (LEDs) 76 that produce energy curtain 64 in response to driving signals 54 from controller 46. LEDs 76 may produce conical infrared beams 78 having angles of between 25° and 30° and wavelengths of 940 or 950 nanometers, and are arranged so that beams 78 are parallel and share a common vertical plane. Operating power for each LED 76 is about four to six milliwatts. A cylindrical lens 80 horizontally focusses and vertically diverges the conical beams 78 from LEDs 76 to produce energy curtain 64 having a vertical angle of about 38° and a horizontal angle & of about 5°-10°. Emitter 68 includes multiple LEDs 76 to increase vertical angle a λ , and to increase the intensity of energy curtain 64 which, in turn, increases the range R at which front emitter/receiver unit 60 can detect obstructions. Each receiver 70 includes a biconvex lens 82 that focusses incoming energy into a parallel beam directed at a band pass filter 84 that passes energy having wavelengths from about 930-950 nanometers. From band pass filter 84, the parallel beam is directed to a second biconvex lens 86 that focusses the beam on a photo IC 88 that produces a voltage signal which varies with the intensity of the beam. Referring also to Fig. 7, photo IC 88 includes a photodiode 90 that produces a voltage in response to the beam and an amplifier 92 that amplifies that voltage. The output of amplifier 92 passes through a 38 kHz bandpass filter 94 before being applied to the input of an integrator 96 that, in combination with a comparator 98, acts as a Schmitt trigger. The output of comparator 98 is supplied to a drive transistor 100 that toggles the output voltage 102 of photo IC 88 between a high value of about five volts when less than a threshold amount of energy is being received to a low value of about zero volts when more than the threshold amount of energy is being received. Photo IC 88 is implemented using an IS1U60 OPIC sensor available from Sharp. Because each receiver 70 has a conical field of view of about 12°, two receivers 70 are employed to provide a suitable field of view. The outputs 102 of receivers 70 are combined by a logical AND operator 104 to produce a detection signal 56. Because outputs 102 have a low value when energy is being detected, detection signal 56 has a high value when neither receiver 70 is detecting energy, and otherwise has a low value. As illustrated in Fig. 8, except for the positioning of LEDs 76, rear emitter/receiver unit 64 is identical to front emitter/receiver unit 60. LEDs 76, though still sharing a vertical plane, are not arranged to produce parallel beams 78. Instead, LEDs 76 are arranged so that their beams 78 converge at lens 80 and then diverge from lens 80. This arrangement results in an energy curtain 66 having a wider vertical angle α 2 than energy curtain 62 produced by front emitter/receiver unit 60. In an alternative approach, as illustrated in Figs. 9A-9C, emitter/receiver units 60, 64 are implemented using a compact emitter/receiver unit 106 that is only 1.4 inches wide by 0.75 inches deep by 1.1 inches high. Like units 60, 64, unit 106 includes four LEDs 76 and a photo IC 88. Unit 106 also includes a common lens 108 used by LEDs 76 and photo IC 88, and a receiver lens 110 used by photo IC 88. To prevent beams 78 from LEDs 76 from directly striking photo IC 88, photo IC 88 is positioned in a recess 110 within a housing 112 of unit 106. Due to its compact size, unit 106 is extremely easy to install. Referring to Fig. 10, controller 46 operates obstruction detection system 52 according to a procedure 120. Because obstruction detection system 52 is only active when a window is being closed, controller 46 does not activate obstruction detection system 52 until controller 46 generates or receives a close request (step 122) . As discussed above, controller 46 generates automatic close requests in response to signals from, for example, rain sensor 34, and to implement features such as anti air bind. In addition, the driver or another occupant of automobile 10 can cause controller 46 to generate an automatic, express close request by merely touching a switch 24, or a manual close request by continually pressing a switch 24. Thus, as a next step, controller 46 determines whether the close request is an automatic close request or a manual close request (step 124) . Typically, a close request from a switch 24 is deemed to be a manual request if switch 24 is pressed for more than three tenths of a second. If the close request is a manual close request (step 124) , controller 46 sends a close signal to motor 22 that controls the window associated with the pressed switch (step 126) . The close signal causes motor 22 to close the window by an incremental amount. After sending the close signal, controller 46 determines whether there is still a close request (i.e., the driver is still pressing switch 24) (step 122) , and, if so, repeats the process. The manual close request, which enables a window to be closed without attempting to detect obstructions, provides a useful fail safe in that it ensures that a window can be closed in the event of a failure in obstruction detection system 52. If the close request is an automatic close request (step 124) , controller 46 activates the appropriate emitter 68 and determines whether emitter 68 is operating correctly (step 128) . As illustrated in Fig. 11A, controller 46 activates emitter 68 by sending a driving signal 54 that includes a series of 38 kHz pulses 150 that are frequency modulated on a train of lower frequency pulses 152 having a period P and a duty cycle of about fifty percent. Period P for a front emitter/receiver unit 60 may range between 40 milliseconds and 60 milliseconds, and period P for a rear emitter/receiver unit 64 may range between 50 milliseconds and 100 milliseconds. Controller 46 determines whether emitter 68 is operating correctly by monitoring the detection signal 56 produced by receivers 70. As illustrated in Fig. 11B, when emitter 68 is operating correctly, detection signal 56 includes a series of pulses 154 having a period P. Pulses 154, which correspond roughly to pulses 152 of driving signal 54 and have low voltage values when pulses 152 have high voltage valves, result from detection by photo IC 88 of a reflected portion of an energy curtain 62. When emitter 68 is not operating correctly, as illustrated in Fig. 11C, detection signal 56 does not include pulses and instead remains at a high voltage value. This condition occurs when emitter 68 is not producing an energy curtain 62, or when emitter 68 is blocked so that no portion of energy curtain 62 can be reflected to photo IC 88. If emitter 68 is not operating correctly (step 130) , controller 46 performs no further action, and instead waits for a new close request (step 122) . At this time, if desired, the driver or other occupant of automobile 10 could override controller 46 by manually pressing a window switch 24. If emitter 68 is operating correctly (step 130) , controller 46 monitors detection signal 56 and determines t, the length of a detection pulse (step 132) . The length of a detection pulse is related to the intensity of energy incident on photo IC 88, and, because obstructions reflect energy toward photo IC 88, increases when an obstruction is present. Thus, controller 46 detects obstructions by comparing t to T', an initialization value related to the length of a detection pulse produced by photo IC 88 when a window 16 is free of obstructions (step 134) . T' is generated in an initialization procedure during installation of system 44. During this procedure, emitter 68 is activated and detection signal 56 is monitored while window 16 is closed under obstruction free conditions. T, the average value of t while window 16 is being closed, is determined from detection signal 56. T' is then generated as: T' = T + 2-/T, where the square root term allows some deviation in the value of an acceptable t and thereby accounts for deviations that could be caused by variations in temperature or system voltage. T' could be generated using other approaches. For example, T' could be varied with different window positions to more precisely account for reflections caused by window 16. In addition, to void the need for nonvolatile memory to store T', T' could be determined each time that system 44 is powered up (i.e., connected to the battery of automobile 10). Also, to optimize performance of system 44 under different operating conditions, T' could be generated in response to a command from the driver of automobile 10. T' accounts for background noise and variations in system 44 that could affect system performance. Other background effects, such as sunlight, which, in an improperly designed system, could adversely affect operation, are handled by the filters 84, 94 included within receiver 70. Filter 84 ensures that only energy having a wavelength similar to that produced by an emitter 68 can be incident on photo IC 88. However, sunlight includes sufficient amounts of energy within the wavelength band passed by filter 84 to saturate photo IC 88 and prevent detection of reflections from energy curtain 62 (sunlight includes approximately ten to fifteen milliwatts in the wavelength band from 930 to 950 nanometers, while emitter 68 produces approximately sixteen to twenty four milliwatts in this band) . To eliminate the effects of sunlight, receiver 70 also includes filter 94, which only passes energy that, like driving signal 54, is modulated at 38 kHz. Thus, sunlight could only affect operation of receiver 70 if the sunlight were somehow modulated at 38 kHz, a situation that is extremely unlikely to occur. Moreover, in the unlikely event that sunlight was able to saturate receiver 70, this would only prevent automatic closing of window 16, and would impose no risk that window 16 would be accidentally closed on an obstruction such as a child's hand. If controller 46 determines that t is greater than T' (step 134) , this indicates that an obstruction might be present in window 16, and controller 46 responds by incrementing a miscompare count (step 136) . If the incremented miscompare count is greater than two (step 138) , controller 46 determines that an obstruction is actually present, and responds by cancelling any outstanding close signals and sending a signal to motor 22 that causes motor 22 to fully open window 16 (step 140) . Thereafter, controller 46 waits for additional close requests (step 122) . If the incremented miscompare count is not greater than two (step 138) , controller 46 sends a close signal to the motor 22 corresponding to the window associated with the close request (step 142) . The close signal causes motor 22 to close the window by an incremental amount. Typically, controller 46 operates at a speed at which consecutive close signals overlap so that, absent the detection of an obstruction, the close signals cause motor 22 to close window 16 in a smooth, continuous manner. After sending the close signal (step 142) , controller 46 determines whether window 16 is closed (step 144) . Typically, controller 46 makes this determination by detecting changes in the electrical characteristics of motor 22. For example, physical resistance caused by the window reaching the closed position results in an increased load on motor 22 that is detectable by controller 46. If the window is not closed, controller 46 repeats the automatic closing process by monitoring detection signal 56 and determining t (step 132) . If the window is closed, controller 46 waits for additional close requests (step 122) . If controller 46 determines that t is less than or equal to T' (step 134) , controller 46 responds by resetting the miscompare count (step 146) . By doing so, controller 46 ensures that only three consecutive miscompares will be treated as an actual obstruction, and minimizes the occurrence of incorrect obstruction detections. Thereafter, controller 46 sends a close signal to motor 22 (step 142) and checks to see if window 16 is closed (step 144) . Referring to Fig. 12, controller 46 can be implemented using a processor 156 that communicates with other components of system 44 through ports 157 connected to an I/O interface 158. Specifically, I/O interface 158 communicates with driver (D) switch 24, passenger (P_D) switch 24, rear left (RL_D) switch 24, rear right (RR_D) switch 24, and child guard (CG) switch 160 of control panel 26; passenger (P) switch 24; rear left (RL) switch 24; rear right (RR) switch 24; sunroof (SR) switch 28; sunroof fully closed (SRFC) indicator 162; ignition (IS) switch 32; temperature sensor 36; rain sensor 34; sunroof (SR) , driver (D) , passenger (P) , rear left (RL) , and rear right (RR) driving signals 54 and detection signals 56; audible feedback unit 58; and anti air bind (AAB) switch 164, which has a high value when all doors 12, 14 are closed, and a low value when a door 12, 14 is open. Because switches 24, 28 operate in three modes (open, close, and inactive) , I/O interface 158 communicates their status to processor 156 through pairs of bits of ports 157. I/O interface 158 communicates the status of each of the remaining sensors through single bits of ports 157. Controller 46 also includes a rain sensor interface 166 and a temperature sensor interface 168. Because rain sensor 34 is a capacitor having a value that changes in the presence of rain, interface 166 includes an oscillator 170 that drives rain sensor 34 and a sensor 172 that detects a change in the capacitance of rain sensor 34. Temperature sensor 36 is a resistor that varies with temperature, and interface 168 includes a heat detector 174 that compares the resistance of temperature sensor 36 to a resistance corresponding to 95° F. and produces a high valued output when the resistance of temperature sensor 36 indicates a temperature in excess of 95° F. Interface 168 also includes a cold detector 176 that compares the resistance of temperature sensor 36 to a resistance corresponding to 55° F. and produces a high valued output when the resistance of temperature sensor 36 indicates a temperature that is less than 55° F. Processor 156 drives motors 22 through a port 178 that is connected to a set of relays 180. Relays 180 connect to window motors 22 through an eight pin port 182. Each window 16, 18 is operated by two unidirectional motors 22, one for opening and one for closing, so two relays 180 correspond to each window 16, 18. Relays 180 connect to sunroof motor 22, a twelve volt power supply (the battery of automobile 10) , and electrical ground through a four pin port 184. Sunroof motor 22 is reversible, so two relays 180, one for opening sunroof 20 and one for closing sunroof 20, correspond to sunroof 20. By providing a central control for motors 22, controller 46 produces substantial savings in wiring and power consumption. For example, instead of each switch 24 being connected to its corresponding motors 22 with high voltage, heavy gauge wire, switches 24 are connected to controller 46 using low voltage, light gauge wire. In addition, switches 24 are only required to handle low voltages and can therefore be implemented using less expensive and lighter materials. Essentially, processor 156, which is implemented using an Intel 83C552C processor, operates in one of three modes: a parking mode in which processor 156 automatically opens and closes windows 16, 18 and sunroof 20 in response to rain, heat, motion, and light; a driving mode in which processor 156 provides one touch, express opening and closing of windows 16, 18 and sunroof 20; and an anti air bind mode in which processor 156 automatically cracks open rear windows 18 in response to an open door 12, 14. When processor 156 enters parking mode (in response to ignition switch 32 moving to the off position) , processor 156 provides security closing of all windows 16, 18 and sunroof 20. Referring to Fig. 13, processor 156 determines its operational mode according to a procedure 200. If a door 12, 14 is open (step 202), processor 156 performs anti air bind operations (step 204). If a door 12, 14 is not open (step 202) , processor 156 determines whether ignition switch 32 is on (step 206) . If ignition switch 32 is on, processor 156 performs driving mode operations (step 208) . If ignition switch 32 is off, processor 156 performs parking mode operations (step 210) . Upon completion of anti air bind (step 204) , driving (step 208) , cr parking (step 210) operations, processor 156 determines whether a door is open (step 202) and repeats procedure 200. Referring to Fig. 14, when processor 156 performs anti air bind operations (step 204) , processor 156 first opens windows 18 (step 212) . Thereafter, processor 156 waits until no doors 12, 14 are closed (step 214). When all doors 12, 14 are closed, processor 156 closes rear windows 18 (step 216) and exits anti air bind operations. Processor 156 closes rear windows 18 by sequentially generating automatic close requests for each rear window 18 and responding to the automatic close requests and detecting obstructions according to procedure 120, as illustrated in Fig. 10 and discussed above. Referring to Fig. 15, when processor 156 performs driving mode operations (step 208) , processor 156 first checks to see if a valid open switch has been pressed (step 218) . When child guard (CG) switch 160 is active, valid open switches include certain (D, P_D, RL_D, RR_D, and P) window switches 24 and sunroof (SR) switch 28. When child guard (CG) switch 160 is inactive, valid open switches also include the RR and RL window switches 24 (child guard (CG) switch 160 disables RR and RL window switches 24) . If a valid open switch has been pressed (step 218) , processor 156 monitors the switch until the switch is either released or pressed for longer than three tenths of a second (step 220) . If the switch is pressed for longer than three tenths of a second, processor 156 manually opens the window associated with the pressed switch (step 222) by activating the corresponding motor 22 until the window reaches the fully open position or the switch is released. If the switch is pressed for less than three tenths of a second (step 220) , and the pressed switch is not the RL_D window switch 24 (step 224) , processor 156 express opens the window associated with the pressed switch (step 226) by activating the corresponding motor 22 until the window reaches the fully open position or the switch is pressed again. If the switch is pressed for less than three tenths of a second (step 220) , and the pressed switch is the RL_D window switch 24 (step 224) , processor 156 express opens all of the windows (step 228) by sequentially activating the open motors 22 until all of the windows reach the fully open position or another switch is pressed. Processor sequentially activates motors 22 to avoid an excessive drain on the battery of automobile 10 that could be caused by simultaneously activating all motors 22. After responding to any pressed valid open switches, processor 156 checks for pressed valid close switches (step 230) . The valid close switches correspond exactly to the valid open switches discussed above. If a valid close switch has been pressed, processor 156 monitors the switch until the switch is either released or pressed for longer than three tenths of a second (step 232) . If the switch is pressed for longer than three tenths of a second, processor 156 manually closes the window associated with the pressed switch (step 234) by generating a manual close request and responding according to procedure 120. If the switch is pressed for less than three tenths of a second (step 232) , and the pressed switch is not the RL_D window switch 24 (step 236) , processor 156 express closes the window associated with the pressed switch (step 238) by generating an express close request and responding according to procedure 120. Though not illustrated in the discussion of procedure 120, the express close operation, like the express open operation, can be halted by pressing the switch again. If the switch is pressed for less than three tenths of a second (step 232) , and the pressed switch is the RL_D window switch 24 (step 236) , processor 156 express closes all of the windows (step 240) by sequentially generating automatic close requests and responding according to procedure 120. Referring to Figs. 16A-16B, when processor 156 performs parking mode operations (step 210) , processor 156 first initializes a timer to thirty seconds (step 242) . Processor 156 then waits either for a switch 24 to be pressed to deactivate security closing (step 244) or for the timer to expire (step 246) . If the timer expires before a switch 24 is pressed, processor 156 performs the security close feature by express closing all windows, and reinitializes the timer to thirty seconds (step 248) . As discussed above, processor 156 express closes all windows by generating sequential automatic close requests. After reinitializing the timer (step 248) , processor 156 waits either for a switch 24 to be pressed to activate the heat open feature (step 250) or for the timer to expire (step 252) . If the timer expires before a switch is pressed, processor 156 proceeds to further operations. If a switch is pressed before the timer expires (steps 244, 250), processor 156 provides feedback in the form of an audible tone at feedback unit 58 (step 254) and activates the heat open feature (step 256) . Next, if the heat open feature is activated and the temperature in automobile 10 is greater than 95° F. (step 258) , and it is not raining (step 260) , processor 156 sequentially express opens all windows 24 to positions previously designated by the driver of automobile 10 (step 262) . (As discussed above, the driver can designate the extent to which windows 24 open by pressing buttons multiple times.) Finally, if it is raining (step 264) , if the temperature is less than 55° F. (step 266) , if motion is detected (step 268) , or if it is dark (step 270) , processor 156 express closes all windows by sequentially generating automatic close requests for each window and responding according to procedure 120 (step 272) . Thereafter, if no door 12, 14 is open (step 274) and ignition switch remains off (step 276) , processor 156 repeats the process by checking for a temperature in excess of 95° F. (step 258) . Typically, occupant controlled opening and closing of windows 16, 18 is disabled when processor 156 is in the parking mode. However, if desired, these features could be easily implemented therein. Referring to Figs. 17-18, obstruction detection for sunroof 20 is achieved with a dual emitter/dual receiver configuration. Two emitter/receiver units 300, each including an emitter 302 and a receiver 304, are positioned in the front corners of sunroof frame 306. Emitter/receiver units 300 are oriented so that an energy beam produced by the emitter 302 of one emitter/receiver unit 300 is incident on the receiver 304 of the other emitter/receiver unit 300. A barrier 308 is provided between emitter 302 and receiver 304 so that the energy beam from the emitter 302 of an emitter/receiver unit 300 is not directly incident on the receiver 304 of the same emitter/receiver unit 300. Each emitter 302 includes an infrared LED 76 that produces a conical infrared beam having an angle of 25°- 30° and a wavelength of 950 nanometers. A suitable LED 76 is model number GL538 from Sharp. The housing of emitter 302 limits the conical angle of the infrared beam produced by emitter 302 to about 10°. Each receiver 304 includes a biconvex lens 82 that focusses incoming energy into a parallel beam directed at a high pass filter 310 that passes energy having wavelengths in excess of 750 nanometers. From high pass filter 310, the parallel beam is directed to a second biconvex lens 86 that focusses the beam on a photo IC 88 that produces a voltage signal which varies with the intensity of the beam. As discussed with respect to the window system, photo IC 88 produces a voltage having a high value of about five volts when less than a threshold amount of energy is being received to a low value of about zero volts when more than the threshold amount of energy is being received. In operation, emitters 302 are driven by 38 kHz signals that are modulated by a series of 400 Hz pulses that are configured so that only one emitter 302 is driven at any time. Obstructions are detected when a beam from an emitter 302 of one of the emitter/receiver units 300 is interrupted and prevented from reaching the receiver 304 of the other emitter/receiver unit 300 so that the output of the receiver 304 remains high. Obstructions are also detected when a beam from an emitter 302 of one of the emitter/receiver units 300 is reflected back to the receiver 304 of the same emitter/receiver unit 300 so that the output of the receiver 304 changes to a low value. Use of two receivers 304 and two emitters 302 operating in an alternating fashion eliminates any risk that sunlight will cause the system to fail to detect an obstruction. As discussed with respect to the window system, the 38 kHz band pass filter in photo IC 88 prevents sunlight from being detected by photo IC 88. However, sunlight can still saturate photo IC 88 and thereby prevent photo IC 88 from detecting the 38 kHz signal from the emitter 302. By using two receivers 304 positioned so that sunlight can only strike one of them at any given time, the dual emitter/dual receiver system eliminates the effects of sunlight. An obstruction free condition, F, for sunroof 20 can be expressed as a logical equation: F = E1RΪR2 + E2R2RΪ where El and E2 are the emitters 302 in, respectively, the front left and front right corners and have values of logical one while emitting a 38 kHz modulated signal, and Rl and R2 are the receivers 304 in, respectively, the front right and front left corners of sunroof frame 306 and have values of logical one while receiving a 38 kHz modulated signal. According to this equation, sunroof 20 is obstruction free when the front left emitter 302 (El) is emitting, the front right receiver 304 (Rl) is receiving, and the front left receiver 304 (R2) is not receiving, or when the front right emitter 302 (E2) is emitting, the front left receiver 304 (R2) is receiving, and the front right receiver 304 (Rl) is not receiving. This equation works even when a receiver 304 is saturated by sunlight and unable to receive a signal from an emitter 304. For example, when the front left receiver 304 (R2) is saturated, R2 always has a value of logical zero and the equation reduces to: F = E1R1 . Thus, when a receiver 304 is saturated by sunlight, the sunroof obstruction detection system still functions. Because it does not require a cylindrical lens 80, the sunroof obstruction detection system is substantially less expensive than the window obstruction detection system. However, due to the conical nature of the beams produced by emitters 302, the sunroof obstruction detection system is unsuited for use in a window. Moreover, due to difficulties associated with installing the window system in a way that would not result in false detections caused by the driver's head or the passenger's head, the window obstruction detection system would be difficult to use in a sunroof. While, as discussed above, control of sunroof 20 can be integrated into system 44, control of sunroof 20 can also be implemented using a separate system 312, as illustrated in Fig. 19. System 312 includes a control unit 314 that receives input from ignition switch 32, sunroof switch 28, rain sensor 34, temperature sensor 36, receivers 304, and a motor feedback signal processing unit 316. In response to these inputs, control unit 312 operates emitters 302 and a motor driver 318 that drives the sunroof motor 22. As illustrated in Fig. 20, control unit 314, which is an Intel 8051 processor, implements a main procedure 320. After initialization (step 322), if ignition switch 32 is on (step 324) , control unit 314 performs a driving procedure (step 326) , and, if ignition switch 32 is off (step 324) , control unit 314 performs a parking procedure (step 328) . Operations in driving procedure 326 (Fig. 21) are based on the position of sunroof switch 28, which can be in a close position, an open position, or an inactive position. If switch 28 is in the close position (step 330) , control unit performs a procedure to close sunroof 20 (step 332) and returns to the main procedure (step 334) . If switch 28 is in the open position (step 332) , control unit performs a procedure to open sunroof 20 (step 336) and returns to the main procedure (step 334) . If switch 28 is in the inactive position, control unit 314 returns to the main procedure (step 334) . Sunroof 20 can be in an opened position, a closed position, or a vented position. When sunroof 20 is in the closed position, setting switch 28 to the open position will cause sunroof 20 to move to the opened position, and setting switch 28 to the close position will cause sunroof 20 to move to the vented position. When sunroof 20 is in the opened position, setting switch 28 to the close position will cause sunroof 20 to move to the closed position. Finally, when sunroof 20 is in the vented position, setting switch 28 to the open position will cause sunroof 20 to move to the closed position. In close sunroof procedure 332 (Fig. 22) , if sunroof 28 is in the closed position (step 340) , control unit 314 performs a vent open procedure (step 342) . If sunroof 28 is not in the closed position (step 340) , control unit 314 performs a slide close procedure (step 344) . After performing the vent open procedure (step 342) or the slide close procedure (step 344) , control unit 314 returns to the previous procedure (step 346) . In open sunroof procedure 338 (Fig. 23) , if sunroof 28 is in the vented position (step 348) , control unit 314 performs a vent close procedure (step 350) . If sunroof 28 is not in the vented position (step 348) , control unit 314 performs a slide open procedure (step 352) . After performing the vent close procedure (step 350) or the slide open procedure (step 352) , control unit 314 returns to the previous procedure (step 354) . In slide close procedure 344 (Fig. 24) , control unit 314 sets a ripple counter to an increment mode (step 346) . Control unit 314 uses the ripple counter, which counts current ripples in motor 22 and is supplied by motor feedback signal processing unit 316, to detect that sunroof 20 has reached a fully open or fully vented position. Control unit 314 also enables (step 348) a ripple interrupt procedure 349 (Fig. 28) that control unit 314 uses to increment or decrement the ripple counter each time a ripple occurs, and to pressure detect an obstruction in the path of sunroof 20. After enabling ripple interrupt 349 (step 348) control unit 314 signals motor driver 318 to activate motor 22 to close sunroof 20 (step 350) and determines whether switch 28 was touched or pushed (step 352) . If switch 28 was pushed, this indicates that manual closing was selected, and control unit 314 allows motor driver 318 to continue to close sunroof 20 until switch 28 is released (step 354) or sunroof 20 reaches the fully closed position (step 356) . When either of these conditions occur, control unit 314 signals motor driver 318 to deactivate motor 22 and stops the ripple counter (step 358) before returning to the previous procedure (step 360) . If switch 28 was touched, this indicates that express closing was selected, and control unit 314 allows motor driver 318 to continue to close sunroof 20 until switch 28 is touched again (step 362) , an obstruction is detected (F = 0) (step 364) or sunroof 20 reaches the fully closed position (step 366) . When switch 28 is touched again (step 362) or sunroof 20 becomes fully closed (step 366) , control unit 314 signals motor drivers 318 to deactivate motor 22 and stops the ripple counter (step 358) before returning to the previous procedure (step 360) . When an obstruction is detected (step 364) , control unit 314, after signaling motor driver 318 to deactivate motor 22 and stopping the ripple counter (step 368) , performs the slide open procedure (step 352) . In vent open procedure 342 (Fig. 25) , control unit 314 sets the ripple counter to an increment mode (step 370), enables ripple interrupt 349 (step 372), signals motor driver 318 to activate motor 22 to drive sunroof 20 in the close direction (step 374) , and sets an internal vent flag that indicates that sunroof 20 is in the vented position and is automatically reset when sunroof 20 reaches the fully closed position (step 376) . Next, control unit 314 determines whether switch 28 was touched or pushed (step 378) . If switch 28 was pushed, this indicates that manual closing was selected, and control unit 314 continues to close sunroof 20 until switch 28 is released (step 380) or the ripple counter indicates that sunroof 20 is in the fully vented position (step 382) . When either of these conditions occur, control unit 314 signals motor driver 318 to deactivate motor 22 and stops the ripple counter (step 384) before returning to the previous procedure (step 386) . If switch 28 was touched, this indicates that express venting was selected, and control unit 314 allows motor driver 318 to continue to vent sunroof 20 until switch 28 is touched again (step 388) or the ripple counter indicates that sunroof 20 is in the fully vented position (step 390) . When either of these conditions occur, control unit 314 signals motor driver 318 to deactivate motor 22 and stops the ripple counter (step 384) before returning to the previous procedure (step 386) . In slide open procedure 352 (Fig. 26) , control unit 314 sets the ripple counter to a decrement mode (step 392) , enables ripple interrupt 349 (step 394) , and signals motor driver 318 to activate motor 22 to drive sunroof 20 in the open direction (step 396) . Next, control unit 314 determines whether switch 28 was touched or pushed (step 398) . If switch 28 was pushed, this indicates that manual closing was selected, and control unit 314 continues to close sunroof 20 until switch 28 is released (step 400) or the ripple counter indicates that sunroof 20 is in the fully open position (step 402) . When either of these conditions occur, control unit 314 signals motor driver 318 to deactivate motor 22 and stops the ripple counter (step 404) before returning to the previous procedure (step 406) . If switch 28 was touched, this indicates that express opening was selected, and control unit 314 allows motor driver 318 to continue to open sunroof 20 until switch 28 is touched again (step 408) or the ripple counter indicates that sunroof 20 is in the fully opened position (step 410) . When either of these conditions occur, control unit 314 signals motor driver 318 to deactivate motor 22 and stops the ripple counter (step 404) before returning to the previous procedure (step 406) . In vent close procedure 350 (Fig. 27) , control unit 314 sets the ripple counter to the decrement mode (step 412) , enables ripple interrupt 349 (step 414) , and signals motor driver 318 to activate motor 22 to drive sunroof 20 in the open direction (which closes sunroof 20 from the vented position) (step 416) . Next, control unit 314 determines whether switch 28 was touched or pushed (step 418) . If switch 28 was pushed, this indicates that manual closing was selected, and control unit 314 allows motor driver 318 to continue to close sunroof 20 until switch 28 is released (step 420) or sunroof 20 reaches the fully closed position (step 422) . When either of these conditions occur, control unit 314 signals motor driver 318 to deactivate motor 22 and stops the ripple counter (step 424) before returning to the previous procedure (step 426) . If switch 28 was touched, this indicates that express closing was selected, and control unit 314 continues to close sunroof 20 until switch 28 is touched again (step 428) , sunroof 20 reaches the fully closed position (step 430) , or ripple interrupt 349 sets a stop flag after pressure detecting an obstruction (step 432) . When switch 28 is touched again (step 428) or sunroof 20 becomes fully closed (step 430) , control unit 314 signals motor driver 318 to deactivate motor 22 and stops the ripple counter (step 424) before returning to the previous procedure (step 426) . When ripple interrupt 349 sets the stop flag (step 432) , which indicates that an obstruction is present in the path of sunroof 20, control unit 314 responds by performing the vent open procedure (step 342) . Ripple interrupt 349 (Fig. 28) , when enabled, is called by control unit 314 each time that a ripple is detected by motor feedback signal processing unit 316. Depending on whether the ripple counter is in an increment or decrement mode (step 434) , control unit 314 increments (step 436) or decrements (step 438) the ripple counter. Next, control unit 314 calculates the present ripple frequency (step 440) based on the time that has expired since ripple interrupt 349 was last called. If the present ripple frequency is smaller than the ripple frequency from when ripple interrupt 349 was previously called by more than a predetermined threshold amount (step 442) , this indicates that motor 22 is facing increased resistance as would be caused by an obstruction in the path of sunroof 20, and control unit 314 responds by setting the stop flag (step 444) and returning to the previous procedure (step 446) . In parking procedure 328, control unit 314 starts a thirty second timer (step 448) and waits for an occupant of automobile 10 to press button 28 to deactivate security closing (step 450) or for the timer to expire (step 452) . If the timer expires, control unit 314 performs a security close of sunroof 20 (step 454) , starts another thirty second timer (step 456) , and waits for an occupant of automobile 10 to press button 28 to activate heat opening and rain closing (step 458) or for the timer to expire (step 460) . If the timer expires, control unit 314 powers down (step 462) and waits to be reactivated by ignition switch 32 turning on. If an occupant of automobile 10 presses switch 28 to deactivate security closing (step 450) or to activate to activate heat opening and rain closing (step 458) , control unit 314 responds by causing beeper 58 to beep once (step 464) . Control unit 314 then waits for an occupant of automobile 10 to press switch 28 to indicate that sunroof 20 should be fully opened during heat opening (step 466) or for the timer to expire (step 468) . If switch 28 is pressed, control unit 314 causes beeper 58 to beep once (step 470) and sets the mode for heat opening to fully open (step 472) . If the timer expires, control unit 314 set the mode for heat opening to partially open (step 474) . Thereafter, control unit 314 powers down and waits to be reactivated by a signal from rain sensor 34 or temperature sensor 36, or by ignition switch 32 turning on. With reference to Fig. 30, an alternative system 1010 includes an electromagnetic energy signal transmitter 1012, a laser signal receiver 1014, a signal detection unit 1016, a signal amplifier 1018, a control unit 1020, a vent element power unit 1022, a vent element 1024, a signal modulation unit 1026, and a laser driver unit 1028. The electromagnetic energy signal transmitter 1012 is a low powered laser such as a laser diode operating in the visible light range. Alternatively, infrared diodes or other light diodes could be used. Low powered laser sources having a minimal impact on the human eye are preferred for safety reasons. The following descriptions including visible light lasers could alternatively include other electromagnetic energy signal sources producing, for example, ultraviolet light or infrared light. In operation, obstructions 1030 entering the path 1032 of the laser beam cause interruptions in the laser beam signal received by the receiver 1014. These interruptions are detected by the detection unit 1016 which transmits a detection signal to the control unit 1020. The control unit 1020 commands the vent element power unit 1022 to respond accordingly. The vent element power unit 1022 may cause the vent element 1024 to stop moving, and subsequently to move in the reverse direction. The signal modulation unit 1026 is connected to the control unit 1020 to enhance operation through feedback control. The modulation unit 1026 preferably provides amplitude, frequency, or phase modulation of the signal, and the detection unit 1016 detects the modulated signals through the use of band pass filters or the like. The control unit may include a microprocessor controller which performs low frequency modulation detection, amplitude modulation detection, pulse code modulation detection, and provides feedback to the signal modulation unit. As shown in Fig. 31, the vent element may be a window 1024 associated with a vehicle door 1033. The closing path 1042 is defined by the top edge 1035 of the door 1033 and the edges 1038, 1040, 1041 of the window frame. The transmitter 1012 and receiver 1014 are positioned together as a single transmitter/receiver unit 1050, and the mirrors 1034, 1036 are positioned to direct the laser energy beam along adjoining straight edges 1038, 1040. As shown in Fig. 32, the vent element may also be a sunroof 1024' within a vehicle roof 1027. The mirrors 1046, 1048 are positioned to direct the laser signal along curved edge 1044. The forward edge 1045 of the sunroof 1024', together with the sunroof opening define the closing path 1042'. Fig. 33 shows the laser beam 1052 of the invention as it is transmitted from the transmitter 1012, reflected off of the mirrors 1036 and 1034 and returned to the receiver 1014. Alternatively the laser beam 1052 may be transmitted along edges 1038 and 1040, then returned doubled back along edge 1040 and finally along edge 1038. In the case where the vent element is a transparent window, the laser energy beam 1052 will pass through the vent element without causing the detection unit to detect an obstruction. Thus the energy signal follows a path that is intersected by two or more edges 1054 of the vent element as the vent element traverses the closing path. In alternative approaches involving opaque vent elements, the laser beam must follow a path that does not intersect the vent element as it traverses the closing path. In this case, the path of the laser beam should be substantially parallel to the plane defined by the vent element. Preferably such a path is adjacent the interior surface of the vent element as opposed to the outside surface which is exposed to the external environment of the vehicle. Temperature variations as well as prolonged vibration may cause misalignment of the energy beam. Two adjustments that can partially alleviate the effects of such misalignment are increasing the sensitivity of the receiver 1014 and permitting the energy beam 1052 to diverge as it travels from the transmitter 1012 to the receiver 1014. Preferably, the energy beam is diverged such that the cross sectional diameter of the energy beam is significantly greater at the receiver than the surface area of the receiving surface 1013 (shown in Fig. 35) of the receiver 1014. Firmly attaching all components to the vehicle also decreases misalignment problems. Ambient energy signals, such as sunlight 1056, may interfere with the obstruction detection system as shown in Fig. 34. If, for example, sunlight 1056 saturates the receiver 1014, then obstructions will not be detected unless a discrimination is made between the ambient signals 1056 and the energy signal 1052 from the transmitter 1012. A discrimination unit 1600, such as a lens 1058, a polarizing filter 1060, and band pass filters 1062 are shown in Fig. 35. The lens 1058 focuses laser light 1032 which is substantially perpendicular to the lens, while diverting ambient light 1056 which is substantially parallel to the lens 1058 away from the focal point of the lens. The polarizing filter 1060 operates in cooperation with another polarizing filter 1064 (shown in Fig. 36) at the transmitter 1012 to further distinguish the transmitted energy beam from ambient signals. The filters 1062 maximize transmission of the laser signal and minimize transmission of ambient signals through absorption. Transmission of the laser light is maximized by having its center wavelength correspond to the wavelength of the laser light. If, for example, the laser light operates at 670 nanometers, then the filters could be selected to provide transmission of only red light (approximately 620 - 700 nm) . Certain of the lenses and filters may be combined in a single colored lens. As shown in Fig. 36, the system may also include a shade configuration 1066 for shading either the transmitter, the receiver, or both from ambient signals 1056. The lens 1065 unit includes a colored polarizing lens as well as the lens 1058 for focusing the beam to a focal point which coincides with the receiving surface 1013 of the receiver 1014. As discussed in connection with Fig. 30, the system includes a signal modulation unit 1026 for modulating the amplitude, frequency, phase, or pulse of the energy signal transmitted from the transmitter. Moreover, the signal may undergo a combination of modulations, such as high frequency (100 khz) / low frequency (10 khz) pulse modulation as shown in Fig. 37, or high frequency pulse / low frequency amplitude modulation as shown in Fig. 38. With reference to Fig. 37, the signal 1800 undergoes a low frequency pulse modulation having a period TI as well as a high frequency modulation having a period T2. The amplitude alternates between Al and A2. The detection unit for detecting the signal 1800 should include two band pass frequency filters: one for each of the frequencies 1/T1 and 1/T2. With reference to Fig. 38, the signal 1900 undergoes a high frequency modulation of period T4 as well as a low frequency modulation of period T4 which oscillates between an amplitude of +/- A3 and +/- A4. The detection unit for detecting the signal 1900 should include a 1/T3 frequency filter, a 1/T4 frequency filter as well as an amplitude filter to detect the periodic amplitude modulations. Pulse modulation may also be employed to discriminate between the transmitted signal and ambient signals. As shown in Fig. 39, the transmitter emits a predetermined series of pulses 1950 which the receiver will receive 1952 as long as there is no obstruction in the closing path. The detection unit is synchronized to detect whether the receiver has received the correct signal. The correct signal is defined as including three or more short pulses of period T5 followed by a series of longer pulses of period T6. Here, the system requires that a series of pulses at predetermined intervals be detected so as to distinguish the transmitted signal from ambient signals which flicker. A flickering ambient signal may result from the vehicle passing trees which are positioned between the vehicle and the sun. Returning to Fig. 39, at time t b the closing operation is commenced until an obstruction is detected by the detection unit. If and when an obstruction is detected, the system responds as described above. As shown in Fig. 40, the signal discrimination may be accomplished by the use of another signal receiver 1068 for receiving only ambient signals. The signal detection unit 1016 would rely on the output of the ambient signal receiver 1068 as a reference. In operation, the analog output of the receiver 1014 is measured with respect to the positive output of the receiver 1068 instead of being measured with respect to ground. Alternatively, the control unit 1020 amy include a microprocessor for digitizing the respective outputs of the receivers 1014 and 1068. The output of the receiver 1068 could then be subtracted from the output of the receiver 1014 by the microprocessor. The system may also include a cylindrical lens 1070 for diverging the laser energy signal as it is emitted from the transmitter 1072 as shown in Fig. 41. The laser energy signal is thus diverged into a substantially planar light beam 1074, any portion 1074' of which may reflect off of an obstruction 1076. This reflection of the signal 1074' is detected by the signal receiver 1078 through the filtering lens 1080. In this case, the detection of an unusually bright reflection corresponds to the detection of an obstruction and the system responds accordingly. As shown in Fig. 42, numerous receiver units 1082a-f are positioned adjacent to the transmitter 1072 and diverging lens 1070. Each receiver/lens unit 1082 includes a receiver 1014 similar to that shown in Fig. 30, and a filter lens unit 1065 similar to that shown in Fig. 36. With reference to Figs. 43 and 44, the multiple receiver units 1082a-f together with the emitter 1072 and diverging lens 1070 (unit 1073) are packaged as a single transmitter/receiver unit 1084 and positioned adjacent to the closing path of an automated vent 1024. In alternative approaches, several transmitter/receiver units 1086a-f may be positioned along one or more edge of a closing path as shown in Fig. 45. Preferably, such units are prepackaged on a single strip 1088 which is attached to the window frame of the vehicle. In another approach, the system includes a fiber optic waveguide 1090 having triangular notches 1092a-f cut as shown in Fig. 46. In operation, the laser would transmit the laser light into the waveguide 1090, and the light would escape through the several notches 1092, thus producing a substantially planar beam 1094. The receiver can either be positioned at the opposite end of the fiber optic waveguide, or adjacent the transmitter. In the latter situation the waveguide includes a mirror 1096 positioned at the opposite end of the waveguide. Again, the presence of an unusually bright signal at the receiver is typically indicative of there being an obstruction in the closing path. In other approaches of the invention, the vent element includes either an attached transmitter, receiver, or waveguide for transmitting the energy signal from a transmitter. In still further approaches, the vent element itself may be comprised of a planar waveguide for transmitting the energy signal. One concern associated with systems incorporating diverging devices is that reflection of the energy beam off of, for example, the interior roof of an automobile, may produce a false detection signal if excess light is reflected to the receiver. Consequently, the detection and control units of such systems should also detect and correct for excessive levels of reflection which remain constant. As shown in Fig. 47, a bi-directional transmitter/receiver unit 1000 comprises a laser emitter 1100, an emitter lens 1102, a light splitter 1104 at 45', a parallel focus lens 1106, a positive piano cylindrical lens 1108, a receiver lens 1110, and a signal receiver 1112. The output from the signal receiver 1112 is amplified by the AC amplifier 1114 and the DC amplifier 1116. The vent control unit 1118 controls the movement of the vent element 1024 responsive to the output of the DC amplifier 1116. An output of the vent control unit 1118 is fed back to the modulation unit 1120 which corrects synchronization and other inconsistencies which are within the range of acceptable variation. If, for example, a low frequency modulation of 25 khz is performed on the transmitted signal and the received signal has a low frequency modulation of 30 khz, then the detection unit will not report an error as the received signal is within an acceptable range (25 +/- 5 khz) . The modulation unit will correct the transmitted signal to return it to 25 khz. Alternatively, the control unit could record the modulation of 30 khz and measure variations and changes from this new base. The bi-directional transmitter/receiver unit 1000 operates as follows. The transmitted light from transmitter 1100 is focused by the lens 1102 and passes through the beam splitter 1104. The light is then focused by the lens 1106 and diverged by cylindrical lens 1108 in to a substantially planar beam 1122. If light reflects off of an obstruction 1124, then the reflected light 1122' will pass back through the cylindrical lens 1108, through the lens 1106 and be split by the beam splitter 1104. A portion of this light will be refracted into the beam splitter and a portion will be reflected by the beam splitter. The reflected portion is directed towards the photo sensitive receiving surface of the receiver 1110. If excessively bright light is received for an extended period of time (such as may be caused by the light reflecting off of the interior of the roof or the sun visor) , the control unit could adjust and measure variations from the increased level of brightness. As shown in Fig. 48 an environment, such as the interior of an automobile, may include ambient reflection 1122". Such reflection could be produced by the interior roof of an automobile 1126. Ambient reflection 1122" will interfere with reflection 1122' from the object 1124 and drench the receiver of the unit 1000 with reflected light 1122' and 1122". The system must differentiate between the object detection reflection 1122' and the ambient reflection 1122". The system achieves this differentiation through use of the feedback control mentioned above. In general, the ambient reflection 1122" does not change as rapidly as the object reflection 1122'. The system employs numerous modulation techniques as described above to detect the variations in object reflected light 1122' with respect to the more steady state ambient reflection 1122". This feedback provides the system with desirable fail-safe features. Referring to Fig. 49, another alternative obstruction detection system 2010 for a vehicle window uses a pair of transducers, transmitter 2012 and receiver 2014. Transmitter 2012 includes an emitter 2016 which emits a narrow beam 2018 of energy which may be sound, ultrasonic, infrared, or light, for example. This beam is received by sensor 2020 in receiver 2014. Transmitter generator circuit 2022 energizes transmitter 2012 to emit beam 2018. To enhance noise rejection a modulation circuit 2024 may be provided to modulate beam 2018. The output from transmitter generator circuit 2022 is also supplied to amplifier and bandpass filter circuit 2026 so that any necessary modulation detection may be accomplished. If an obstacle 2028 should interfere and obstruct beam 2018, this is detected by sensor 2020 in receiver 2014, amplified in amplifier 2030 and submitted to control 2032, which then interrupts the power to window drive 2034. In order to efficiently provide a beam to monitor the nonlinear edge 2040 of window 2030 in door 2036, Fig. 50, having a rectilinear form of two straight edges 2042 and 2044 joined at apex 2046, three transducers 2048, 2050, and 2052 are used. Transducers 2048, 2050, and 2052 are mounted on section 2055 of frame 2054 which receives the edge 2040 of window 2038. Transducer 2050 is the opposite type of transducer as that a transducers 2048 and 2052. Thus if transducer 2050 is a transmitter, transducers 2048 and 2052 are receivers. Conversely, if transmitter 2050 proximate the intermediate portion 2046 is a receiver, then transducers 2048 and 2052 at the terminal portions 2056 and 2058 of edge 2040 are transmitters. In this way, a beam which conforms closely to the contour of window edge 2040 can be effected with a minimum number of transducers. Typically transmitters and receivers for use with infrared are C0X14GE infrared emitter, L14C2GE infrared photo transistor; ultrasonic are P9923 ceramic ultrasonic transducer, P9934 ultrasonic ceramic microphone; sound ar P9922 audio transducer, P9956 electric condenser microphone; laser are P451 laser diodes, BPW38GE photo transistor; and light are P374 light emitter, PN116PA photo transistor. A similar construction is shown with respect to sun roof 2057, Fig. 51, where the sun roof panel 2038a has terminal portions 2056a and 2058a and intermediate portion 2046a. In situations where transducer 2050 is a receiver, there is a need to prevent a blind spot from occurring whereby a finger or other small object might be crushed between the apex or intermediate portion 2046 of window 2038, Fig. 50, and the mating corner 2047 of section 2055, where transducer 2050 is located. In that case a receiver 2050', Fig. 52, having a single sensor 2060 which is generally wide-angle, may be used so that even the smallest finger or similar object necessarily interferes with the beam 2018', 2018" even at its convergence at sensor 2060. Such a receiver is a PN127- SPA NPN photo transistor. Alternatively, a receiver 2050", Fig. 53, may use two sensors 2060', 2060", which are made small enough, approximately 1/4 inch or less, so that each receives a portion of the beam 2018', 2018", but the space 2062 between sensors 2060' and 2060" is made small enough so that even the smallest object to be detected would overlap and block one or the other of sensors 2060' and 2060" and provide the necessary interruption of beam 2018', 2018" to cause the control 2032 to stop the window drive 2034. Such a device is AEM (Automobile Environment Management) System from Prospects Corporation. Whether transducer 2050, Fig. 50, is a transmitter or a receiver, it may be constructed as shown in Fig. 54, where transducer 2050'" has two sensors 2062, 2064 which may as well be emitters, and an interrupter or cover 2066 which is biased by spring 2068 away from sensors or emitters 2062, 2064 in the normal condition. However, when for example an advancing window edge pushes a finger against interrupter 2066, interrupter 2066 will be moved against the force of spring 2068 until it covers sensors 2062 and 2064, thus interrupting beams 2018' and 2018", causing an indication of the presence of an obstacle and causing control 2032 to stop window drive 2034. Such a device is a AEM System from Prospects Corporation. In any corner situation where an obstruction might be so small that it would miss blocking the transmitter or receiver, the transmitter or receiver 2070, Fig. 55, may be mounted in conjunction with a camming surface 2072 which would guide a finger 2074 toward the transistor or receiver, driven by advancing window edge 2076 until finger 2074 is compelled to block beam 2018. Receiver 2070 may be approximately 1/4 inch or less in diameter and surface 2072 may have a radius which varies from 3 inches to 30 inches. Often when a beam 2080, Fig. 56, is being transmitted from transmitter 2082 to receiver 2084, the presence of an obstacle 2086 may not be detected because of ambient noise. For example, if beam 2080 is a light beam then the ambient light from sun 2088 may be such as to overdrive or saturate receiver 2084 so that even if beam 2080 is totally blocked by obstacle 2086, receiver 2084 receives sufficient light so that it provides no indication that an obstruction has occurred. The same type of interference can occur when the beam from transmitter 2082 itself is deflected as beam 2080' Fig. 57, from a surrounding surface 2090, so that receiver 2084 does not detect the presence of obstacle 2086. This may by remedied in a number of ways according to this invention. As shown in Fig. 58, receiver 2084 may be provided with a shade 2092 that blocks not only the rays of sun 2088, but also the deflected beam 2080'. A similar shade 2094 may be used on a housing mounted with transmitter 2082. Alternatively, band pass filter 2096, Fig. 59, may be used to screen from receiver 2084 all but the particular frequency of light, sound or other energy beam, except that originally contained in beam 2080. This of course would not prevent the effect of the deflected beam 2080' because it would have the same frequency as beam 2080 since it is derived from that beam. However, with further improvement of transmitter or receiver construction such an effect can be eliminated. Shade 2092 as well as shade 2094 may be employed along with filter 2096. In another approach, a dual-channel system 2100, Fig. 60, may be used wherein channel A includes transmitter 2082a which transmits beam 2080a toward receiver 20S4a. Channel B is reversed with respect to channel A so that transmitter 2082b is proximate receiver 2084a and receiver 2084b is proximate transmitter 2082a. This is done so that if the ambient energy is incident upon receiver 2084a, it is unlikely that it could also be incident upon receiver 2084b, since 2084b is in the opposite direction from receiver 2084a. When an obstacle 2086 is present, it is possible that beam 2080a could strike obstacle 2086 as indicated at 2080aa and be reflected as also indicated along 2080aa so that it would strike receiver 2084b. The same thing would happen with respect to beam 2080b whereby beam 2080bb would reflected to receiver 2084a. To prevent this crossover between the channels, beam 2080a and beam 2080b are selected to have two different frequencies such as 20 KHz/70 KHz. The receivers are therefore tuned to different frequencies and either one can interfere with the other. Alternatively, as shown in Fig. 61, a dual channel system may be constructed in which channel A and channel B provide energy beams 2080c and 2080d of the same frequency, but their operation is sequenced or multiplexed so that only one beam is on at a time. Thus transmitter 2082c sends out a series of pulses 2082cc, Fig. 62, which are received by receiver 2084c by the series of pulses 2084cc. Any difference between the received pulses 2084cc and the transmitted pulses 2082cc is an indication that an obstacle has been detected. The periods between the pulses, shown crosshatched at 2083cc, are ignored, because during these periods transmitter 2082d is generating pulses 2082dd and receiver 2084d is receiving a like series of pulses 2084dd. The crosshatched areas indicated at 2085dd are the periods during which the input to receiver 2084d is ignored, since they are occurring during the period of the pulses 2082cc, 2084cc. The timing diagram, Fig. 62, also shows the fail safe detection diagnostic operations. The active time period before time line 2102 indicates the active fail safe detection time interval. Before the vent closing operation, a diagnostic OFF/ON signal is send out from the transmitter. The receiver should correspondingly receive the same signal pattern as monitored by the processor 2120. Otherwise, a warning message is generated by processor 2120 and the automatic close-vent operation is blocked. This can be accomplished using a main controller such as microprocessor 2120, Fig. 63, which drives switch control 2122, operates switch 2124 to connect the transmitter generator 2022, Fig. 49, to switch 2124, and selects which of transmitters 2082c and 2082d is turned on in the alternating sequence. A second switch 2126 may be employed, also supervised by switch control 2122, so that the receiver circuits 2026, 2030, 2032 will not even see the signal from the other channel. Switch 2126 may also be used under control of microprocessor 2120, so that if an obstruction is indicated in one of the channels and not the other, indicating that the one channel is giving false readings, switch 2126 can be simply connected continuously to the still credible channel so that only outputs from that channel are processed for determination of whether a true obstruction has occurred. Other embodiments are within the following claims. What is claimed is:

Claims: 1. Apparatus for closing a power driven vent within an opening, the vent including a first closing edge that moves as the vent is closed and the opening including a second closing edge that is contacted by the first closing edge when the vent is in a fully closed position, the apparatus comprising: a detector configured to detect an obstruction at points all along the second closing edge without requiring contact between the obstruction and the vent and to deliver a detection signal when an obstruction is detected, and a controller connected to the detector for receiving the detection signal and delivering a corresponding alarm signal. 2. The apparatus of claim 1, wherein the detector comprises an optical detector. 3. The apparatus of claim 1, wherein the detector detects infrared energy. 4. The apparatus of claim 1, wherein the detector delivers the detection signal in response to an increase in energy received at the detector. 5. The apparatus of claim 4, further comprising an emitter that emits energy, and wherein the detector delivers the detection signal in response to an increase in a reflected portion of the energy received by the detector. 6. The apparatus of claim 4, wherein the detection signal has a characteristic which represents the intensity of the energy received. 7. The apparatus of claim 6, wherein the detector produces pulses having durations related to the intensity of the energy received by the detector, and wherein the detector delivers the detection signal when the duration of one pulse exceeds a predetermined value. 8. The apparatus of claim 6, wherein the detector produces pulses having durations related to the intensity of the energy received by the detector, and wherein the detector delivers the detection signal when the durations of a predetermined number of consecutive pulses exceed the predetermined value. 9. The apparatus of claim 7 or 8, wherein the predetermined value is related to the duration of a pulse when no obstruction is present. 10. The apparatus of claim 9, wherein the predetermined value is related to the average duration of pulses produced when no obstruction is present and the vent moves between an opened position and a closed position. 11. The apparatus of claim 10, wherein the predetermined value includes a correction factor that accounts for variations in the duration of pulses produced when no obstruction is present. 12. The apparatus of claim 9, wherein the predetermined value varies based on the position of the vent. 13. The apparatus of claim 5, wherein the detector and the emitter comprise an integral unit. 14. The apparatus of claim 13, wherein the detector and the emitter share a common lens. 15. The apparatus of claim 1, further comprising initialization means for storing a value indicative of an obstruction free opening. 16. The apparatus of claim 1, wherein the detector delivers the detection signal in response to a decrease in energy received at the detector. 17. The apparatus of claim 1, further comprising an emitter that emits energy, and wherein the detector receives at least a portion of the energy. 18. The apparatus of claim 17, wherein the energy signal is modulated at a first modulation frequency and wherein the detector includes a band pass filter that passes energy modulated at the first modulation frequency. 19. The apparatus of claim 18, wherein the energy signal has a first wavelength and wherein the detector includes a second band pass filter that passes energy having the first wavelength. 20. The apparatus of claim 17, wherein the energy signal has a first wavelength and wherein the detector includes a band pass filter that passes energy having the first wavelength. 21. The apparatus of claim 17, wherein the emitter includes a light emitting diode. 22. The apparatus of claim 17, wherein the emitter includes a laser device. 23. The apparatus of claim 17, wherein the emitter includes a lens that emits the energy signal as a fan shaped energy curtain. 24. The apparatus of claim 23, wherein the energy curtain only covers a portion of the vent. 25. The apparatus of claim 17, wherein the vent comprises a window and wherein the emitter and detector are both positioned in one corner of the opening. 26. The apparatus of claim 25, wherein the vent comprises an automobile window and wherein the emitter and detector are both positioned in the lower front corner of the opening. 27. The apparatus of claim 26, wherein the vent comprises an automobile front window and wherein the emitter and detector are positioned next to each other in a vertical plane. 28. The apparatus of claim 26, wherein the vent comprises an automobile rear window and wherein the emitter and detector are positioned next to each other in a horizontal plane. 29. The apparatus of claim 17, further comprising means for activating the detector and the emitter only when the vent is closing. 30. The apparatus of claim 29, further comprising means for testing the emitter immediately after the activating means activate the emitter. 31. The apparatus of claim 1, further comprising a second detector configured to detect an obstruction at any point along the second closing edge without requiring contact between the obstruction and the vent and to deliver a second detection signal when an obstruction is detected. 32. The apparatus of claim 31, wherein the first and second detectors are arranged so that they are not caused to deliver the first and second detection signals as a result of energy received at the same time. 33. The apparatus of claim 31, further comprising: a first emitter positioned to emit a first energy signal toward the first detector, and a second emitter positioned to emit a second energy signal toward the second detector, wherein the first and second emitters produce the first and second energy signals in an alternating manner, and wherein the controller is connected to the second detector and delivers the alarm signal in response to the first or second detection signals. 34. The apparatus of claim 33, wherein: when the first emitter is emitting the first energy signal, the first detector delivers the first detection signal in response to a decrease in energy received at the first detector, and the second detector delivers the second detection signal in response to a decrease in energy received at the second detector; and when the second emitter is emitting the second energy signal, the first detector delivers the first detection signal in response to an increase in energy received at the first detector, and the second detector delivers the second detection signal in response to an increase in energy received at the second detector. 35. The apparatus of claim 33, wherein the first detector is screened from the second emitter and the second detector is screened from the first emitter. 36. The apparatus of claim 33, wherein the first detector and the second emitter, and the second detector and the first emitter, comprise respective integral units. 37. The apparatus of claim 1, wherein the vent comprises a window. 38. The apparatus of claim 1, wherein the vent comprises a sunroof. 39. The apparatus of claim 1, further comprising means for opening the vent in response to the alarm signal. 40. The apparatus of claim 1, wherein the detector only detects obstructions located in a portion of the opening. 41. The apparatus of claim 1, further comprising means for activating the detector when the vent is closing. 42. The apparatus of claim 1, further comprising a motor for closing the vent. 43. The apparatus of claim 42, further comprising a manual switch, wherein the motor is activated in response to the manual switch. 44. The apparatus of claim 42, further comprising a rain sensor, wherein the motor is activated in response to a signal from the rain sensor. 45. The apparatus of claim 42, further comprising a temperature sensor, wherein the motor is activated in response to a signal from the temperature sensor. 46. The apparatus of claim 42, further comprising a motion detector, wherein the motor is activated in response to a signal from the motion sensor. 47. The apparatus of claim 42, further comprising a light sensor, wherein the motor is activated in response to a signal from the light sensor. 48. Apparatus for closing a power driven vent within an opening, comprising: a first detector configured to detect an obstruction within the opening without requiring contact between the obstruction and the vent and to deliver a first detection signal when an obstruction is detected, a second detector configured to detect an obstruction within the opening without requiring contact between the obstruction and the vent and to deliver a second detection signal when an obstruction is detected, and a controller connected to the first and second detectors for combining the first and second detection signals to produce a combined detection signal and delivering a corresponding alarm signal in response to the combined detection signal, wherein the first and second detectors respond differently to a given obstruction. 49. The apparatus of claim 48, further comprising: a first emitter positioned to emit a first energy signal toward the first detector, and a second emitter positioned to emit a second energy signal toward the second detector. 50. The apparatus of claim 49, wherein the first and second emitters alternatingly emit the first and second energy signals. 51. The apparatus of claim 50, wherein: when the first emitter is emitting the first energy signal, the first detector delivers the detection signal in response to a decrease in energy received at the first detector, and the second detector delivers the detection signal in response to a decrease in energy received at the second detector; and when the second emitter is emitting the second energy signal, the first detector delivers the detection signal in response to an increase in energy received at the first detector, and the second detector delivers the detection signal in response to an increase in energy received at the second detector. 52. The apparatus of claim 49, wherein the first detector is screened from the second emitter and the second detector is screened from the first emitter. 53. The apparatus of claim 49, wherein the first detector and the second emitter, and the second detector and the first emitter, each comprise a respective integral unit. 54. The apparatus of claim 49, wherein the vent comprises a sunroof and the first detector and the second emitter are located in a corner of the opening and the second detector and the first emitter are located in another corner of the opening. 55. The apparatus of claim 49, wherein the energy signals are modulated at modulation frequencies and wherein the detectors include band pass filters that pass energy modulated at the modulation frequencies. 56. The apparatus of claim 48, further comprising means for opening the vent in response to the alarm signal. 57. The apparatus of claim 48, wherein the detector only detects obstructions located in a portion of the opening. 58. The apparatus of claim 48, further comprising means for activating the detector only when the vent is closing. 59. The apparatus of claim 48, further comprising a motor for closing the vent. 60. The apparatus of claim 59, further comprising a manual switch, wherein the motor is activated in response to the manual switch. 61. The apparatus of claim 59, further comprising a rain sensor, wherein the motor is activated in response to a signal from the rain sensor. 62. The apparatus of claim 59, further comprising a temperature sensor, wherein the motor is activated in response to a signal from the temperature sensor. 63. The apparatus of claim 59, further comprising a motion detector, wherein the motor is activated in response to a signal from the motion sensor. 64. The apparatus of claim 59, further comprising a light sensor, wherein the motor is activated in response to a signal from the light sensor. 65. Apparatus for providing a signal when an obstruction is present in an automobile opening within which a power driven vent is being closed, comprising an emitter that emits a fan shaped energy curtain within the opening. 66. The apparatus of claim 65, further comprising: a detector that receives at least a portion of the energy curtain and is configured to detect an obstruction in the opening without requiring contact between the obstruction and the vent and to deliver a detection signal when an obstruction is detected, and a controller connected to the detector for receiving the detection signal and delivering a corresponding alarm signal. 67. The apparatus of claim 66, wherein the detector delivers the detection signal in response to an increase in energy received at the detector. 68. The apparatus of claim 67, wherein the emitter emits the energy curtain away from the detector and the detector delivers the detection signal in response to an increase in a reflected portion of the energy curtain received by the detector. 69. The apparatus of claim 67, wherein the detection signal has a characteristic which represents the intensity of the energy received. 70. The apparatus of claim 69, wherein the detector produces pulses having durations related to the intensity of the energy received by the detector, and wherein the detector delivers the detection signal when the duration of one pulse exceeds a predetermined value. 71. The apparatus of claim 69, wherein the detector produces pulses having durations related to the intensity of the energy received by the detector, and wherein the detector delivers the detection signal when the durations of a predetermined number of consecutive pulses exceed the predetermined value. 72. The apparatus of claim 70 or 71, wherein the predetermined value is related to the duration of a pulse when no obstruction is present. 73. The apparatus of claim 72, wherein the predetermined value is related to the average duration of pulses produced when no obstruction is present and the vent moves between an opened position and a closed position. 74. The apparatus of claim 73, wherein the predetermined value includes a correction factor that accounts for variations in the duration of pulses produced when no obstruction is present. 75. The apparatus of claim 72, wherein the predetermined value varies based on the position of the vent. 76. The apparatus of claim 68, wherein the detector and the emitter comprise an integral unit. 77. The apparatus of claim 66, wherein the detector delivers the detection signal in response to a decrease in energy received at the detector. 78. The apparatus of claim 66, wherein the energy curtain is modulated at a first modulation frequency and wherein the detector includes a band pass filter that passes energy modulated at the first modulation frequency. 79. The apparatus of claim 78, wherein the energy curtain has a first wavelength and wherein the detector includes a second band pass filter that passes energy having the first wavelength. 80. The apparatus of claim 66, wherein the energy curtain has a first wavelength and wherein the detector includes a band pass filter that passes energy having the first wavelength. 81. The apparatus of claim 66, wherein the emitter includes a cylindrical lens that emits the energy curtain. 82. Apparatus for closing a power driven vent within an opening, comprising a detector positioned to detect an obstruction in the opening by receiving energy reflected from the obstruction, the detector producing pulses having durations related to the intensity of the energy received by the detector. 83. The apparatus of claim 82, wherein the detector delivers the detection signal when the duration of at least one pulse exceeds a predetermined value. 84. The apparatus of claim 83, wherein the detector delivers the detection signal when the durations of a predetermined number of consecutive pulses exceed the predetermined value. 85. The apparatus of claim 83, wherein the predetermined value is related to the duration of a pulse when no obstruction is present. 86. The apparatus of claim 85, wherein the predetermined value is related to the average duration of pulses produced when no obstruction is present and the vent moves between an opened position and a closed position. 87. The apparatus of claim 86, wherein the predetermined value includes a correction factor that accounts for variations in the duration of pulses produced when no obstruction is present. 88. The apparatus of claim 85, wherein the predetermined value varies based on the position of the vent. 89. Apparatus for controlling power driven windows of an automobile comprising: driver control switches accessible at the driver's position, separate passenger control switches accessible at a passenger position, and microprocessor control circuitry for responding to switching of the driver and passenger control switches for controlling the power driven windows, the microprocessor control circuitry being programmable in response to the driver control switches and separately programmable in response to the passenger control switches. 90. The apparatus of claim 89, wherein the microprocessor control circuitry responds to switching of the driver control switches when a conflict arises between the driver control switches and the passenger control switches. 91. The apparatus of claim 89, further comprising additional passenger control switches located at two additional passenger positions. 92. The apparatus of claim 91, further comprising a lockout switch at the driver's position, wherein the microprocessor control circuitry ignores switching of the additional passenger control switches in response to the lockout switch. 93. Apparatus for controlling power driven vents in an automobile comprising: driver control switches, and a microprocessor controller connected to the driver control switches to respond to the driver control switches to trigger a circuit for delivery of power to the power driven vents, wherein the driver control switches are not connected directly in the circuit for delivery of power to the power driven vents. 94. The apparatus of claim 93, wherein the microprocessor controller is located remotely from the driver control switches. 95. The apparatus of claim 93, wherein the driver control switches are connected to the microprocessor controller by 20 gauge or finer wire. 96. Apparatus for closing a power driven vent within an opening, comprising: an automatic vent actuator for automatically activating the power driven vent, a manual vent actuator for manually activating the power driven vent, a detector configured to detect an obstruction in the opening without requiring contact between the obstruction and the vent and to deliver a detection signal when an obstruction is detected, and a controller connected to the detector for receiving the detection signal, wherein: when the power driven vent is activated by the automatic vent actuator and the detection signal is received, the controller deactivates the vent, and when the power driven vent is activated by the manual vent actuator, the controller ignores the detection signal. 97. A method of closing a power driven vent within an opening, comprising: activating the vent with a manual actuator or an automatic actuator, detecting an obstruction in the opening without requiring contact between the obstruction and the vent, delivering a detection signal when an obstruction is detected, and when the vent has been actuated by the automatic activator, responding to the detection signal by deactivating the vent, when the vent has been actuated by the manual activator, ignoring the detection signal. 98. A method for conditioning a vehicle to reduce air pressure build up when closing a door of the vehicle, comprising automatically opening a power driven vent in response to the opening of the door. 99. The method of claim 98, further comprising initiating automatic closing of the power driven vent in response to all doors being closed. 100. The method of claim 99, wherein the power driven vent is located within an opening, the method further comprising, after initiating automatic closing of the power driven vent: monitoring the opening for an obstruction in the opening, and opening the power driven vent when an obstruction is detected. 101. The method of claim 100, wherein the obstruction is detected without requiring contact between the obstruction and the vent. 102. The method of claim 98, wherein the vehicle has two front windows and two rear windows, and wherein the power driven vent opened in response to the opening of the door is a rear window. 103. The method of claim 102, wherein both rear windows are opened in response to the opening of the door. 104. A method of monitoring the position of a power driven vent, comprising generating a count of current ripples in a circuit that moves the vent. 105. The method of claim 104, further comprising: generating a measure of current ripples that occur as the power driven vent moves from a first known position to a second known position, and determining the position of the power driven vent by comparing the count of current ripples to the measure of current ripples. 106. The method of claim 105, further comprising incrementing the count when a current ripple occurs and the power driven vent is moving in a first direction, and decrementing the count when a current ripple occurs and the power driven vent is moving in a second direction.

Inventors: CHEN ZIQIANG, CHUANG CLIFF L, LI JAMES S, LU MICHAEL Y, PAN PETER J, SHAO YONGBO, WANG CHONGTIAN, ZHANG JAINJUN, ZHANG JOHN, CHEN, ZIQIANG, CHUANG, CLIFF, L., LI, JAMES, S., LU, MICHAEL, Y., PAN, PETER, J., SHAO, YONGBO, WANG, CHONGTIAN, ZHANG, JAINJUN, ZHANG, JOHN
Applicants: CHEN ZIQIANG, CHUANG CLIFF L, LI JAMES S, LU MICHAEL Y, PAN PETER J, PROSPECTS CORP, SHAO YONGBO, WANG CHONGTIAN, ZHANG JAINJUN, ZHANG JOHN, CHEN, ZIQIANG, CHUANG, CLIFF, L., LI, JAMES, S., LU, MICHAEL, Y., PAN, PETER, J., PROSPECTS CORPORATION, SHAO, YONGBO, WANG, CHONGTIAN, ZHANG, JAINJUN, ZHANG, JOHN
Application year: 1994
Main classification: H02P1
IPC codes: B60J1, B60J7, E05F15, F16P3, H02P7